Charlie Hunnam has described the casting of David Hasselhoff as a porn star in the fourth season of Sons of Anarchy as "a pretty surreal situation".Speaking to Digital Spy about Hasselhoff's cameo as well-endowed adult actor Dondo, Hunnam confessed that he found it strange working alongside one of his childhood heroes."He was exactly as you'd imagine David Hasselhoff to be. He was pretty nice. He was pretty smooth. He was pretty great," Hunnam said."I literally filmed with him for three hours and it was in and out. But it was pretty surreal as a situation. Like everyone else, I grew up watching him every morning on Knight Rider as Michael Knight."Hunnam, who plays Jax in the outlaw motorcycle club drama, claimed that the role wasn't originally intended for Hasselhoff, but that he fitted into the part perfectly."The casting went wrong with the dates and I think Kurt had it in his head that it would be someone fancy in that role. So he went and put his thinking cap on and came up with David Hasselhoff as his replacement," said Hunnam."I think when you see the show and the role it all makes perfect sense. He is playing as close to David Hasselhoff as you can get within the world of Sons of Anarchy. We're not expecting you to believe that he's showing up as some mass crime boss."Sons of Anarchy season three is currently airing in the UK on Wednesdays at 10pm on 5USA. Season four will start in the US in Septmeber on FX.